Motion Of Bodies In Contact - Practice Questions & MCQ

A block of mass m is connected to another block of mass  M  by a spring ( massless ) of spring constant  K . The blocks are kept on a smooth horizontal plane.Initially the blocks are at rest and the spring is unstretched   Then a constant force  F  starts acting on the block of mass  M  to pull it. Find the force of the block of mass  m.

Three blocks A, B and C, of masses 4 kg, 2 kg and 1 kg respectively, are in contact on a frictionless surface, as shown. If a force of 14 N is applied on the 4 kg block, then the contact force between A and B is: